• Korean Journal of Plant Taxonomy
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• v.36 no.2
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• pp.153-161
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• 2006

Two Unrecorded species from Jeju Province are reported: Maesa japonica of Maesaceae which is unrecorded family and Cardamine tanakae of Brassicaceae. Monotypic family Maesaceae, is distinguished from Myrsinaceae and Primulaceae by having pedicels with a pair of bracteoles, flowers without staminodia, semi-inferior ovary and indehiscent fruits with many seeds. M. japonica is readily distinguishable from M. salicifolia in China and M. montana var. formosana in Taiwan and Japan by shapes of blades, corolla and bracteoles, the presence/absence of serrulation of leaf margins, ratio of length of corolla tube and corolla lobes, feature and color of fruit surface. C. tanakae is most similar to Korean endemic C. glechomifolia in morphology, however, the two taxa are readily distinguishable by the number of leaflets of cauline leaves, size of terminal leaflets, number of flowers per inflorescence, the presence of whitish hairs on ovary and fruits.

• Korean journal of applied entomology
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• v.46 no.2
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• pp.269-274
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• 2007

This study was performed to estimate the efficacy of three commercial mating disruptors for the control of oriental fruit moth, Grapholita molesta (Busck), using a food-baited trap to collect field females. Mated female ratios estimated in the mating disruptor-treated areas were compared with the estimates of male trap captures, and both estimates were evaluated on the basis of crop damage measured by shoot tip damage caused by G. molesta. Both males and females were attracted to the food trap-baited with terpinyl acetate in apple orchard. Spermatophore of G. molesta was similar to female bursa copulatrix in size. Though there was more than 95% reduction in male trap captures indicating significant mating disruption, significant crop damage occurred on apple leaf buds, in which more than 35% of captured females were mated. This study demonstrates that assessment of the mated females would be more reasonable to represent the efficacy of mating disruptor(s) than the assessment of the male captures in G. molesta.

• Horticultural Science & Technology
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• v.31 no.3
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• pp.328-336
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• 2013

This study was conducted to evaluate imported tomato $F_1$ cultivars as breeding materials for the resistance to Tomato yellow leaf curl virus (TYLCV) by molecular markers and bioassay. From marker genotyping and disease evaluation of 40 $F_1$ cultivars, most of the cultivars declared as TYLCV-resistance carried heterozygous marker genotype for the TYLCV resistance genes Ty-1, Ty-3, or Ty-3a, and showed low disease rates. Whereas, 4 of 5 $F_1$ cultivars declared as intermediate resistance showed marker genotype for susceptibility and disease rates ranged 18.1-33.3%. However, the xx cultivars showed inconsistency in marker genotype and disease rate. Characterization of horticultural traits of the $F_1$ cultivars with TYLCV-resistance indicated that large-size fruit cultivars were higher in yield and similar in sugar contents and solid-acid ratio compared to a control cultivar preferred in the domestic market, although hardness remained to be a problem. On the other hand, cherry tomato cultivars showed lower yield and brix, but longer internode compared to a control cultivar, indicating that breeding for TYLCV-resistance using these cultivars will require more efforts and time compared to large-sized.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.3
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• pp.177-183
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• 2008

Sodium is known to reduce a plant growth and yields. However, the relationships between physiological response of seedling and salinity stress caused by growing media are not well understood yet. We conducted experiments to investigate change of some parameters including Na, EC, moisture content in media under different air temperature ($15^{\circ}C$, $25^{\circ}C$), and the response of fruit-vegetables such as cucumber, oriental melon on saline conditions originated from horticultural substrate. Volumetric moisture content of media at $15^{\circ}C$ was 70%, but at $25^{\circ}C$ was decreased by 45% within 22 hrs, showing below optimal matric potential, approximately. During reaction time, the increase of Na concentration was significantly greater in saline substrate than in control. The decrease rate of Na concentration according to supplying irrigation water was higher in saline substrate than in control. $CO_2$ assimilation rate and transpiration rate of Korea melon grown in low temperature were decreased with a Na/cation ratio in hydroponic solution. Water saturation deficit was also increased significantly at $15^{\circ}C$ as compare to $25^{\circ}C$. Saline stress during nursery stage induced a reduction of seedling quality, growth and cucumber yield. The results suggest that the relationship between uncontrolled Na uptake of seedling from saline substrate and meteological condition is responsible for saline stress.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.331-337
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• 2023

Physiological disorders in pear fruit are mainly caused by problems during the growing season, such as lack of calcium in the soil, poor drainage, low porosity, vigorous pruning, and excessive fruiting. In this study, soil physicochemical properties and leaf characteristics were analyzed in pear orchards in four regions of Korea where chlorosis symptoms occurred to determine the causes of chlorosis. The color of chlorotic leaves was diagnosed using the naked eye or SPAD and Hunter values. The soil of the chlorotic orchard had a significantly higher soil pH than that of the regular orchard. Although adequate soil depth was not significantly associated with chlorosis, combined with over-fertilization of the soil with lime, it could potentially impair plant iron uptake. Chlorotic leaves had significantly lower iron and calcium contents and significantly higher magnesium contents than those of regular leaves. Therefore, the intensive occurrence of chlorosis during secondary shoot development around June and July when it is hot and humid may be due to impaired iron and calcium absorption, leading to physiological disorders. To solve this problem, avoiding the over-application of lime and applying foliar fertilizers containing chelated iron is recommended.

• Journal of Bio-Environment Control
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• v.20 no.4
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• pp.283-289
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• 2011

This study was conducted to examine the effects of defoliation treatment on the growth and yield of strawberry ($Fragaria{\times}ananassa$ cv. Maehyang and Seolhyang) during nursery period. Leaves of strawberry plantlet had been removed except two, three and four fully expanded leaves until planting date. As the intensity of defoliation was strong, the petiole length was reduced and overgrowth of strawberry plantlet was suppressed. Outer diameter of crown in defoliation treatments significantly decreased but inner diameter of crown was not significant. Number of primary roots of the 3 leaves or 4 leaves defoliation treatment generally tended to increase, but there was not significantly different among treatments. Fresh weight and leaf area in the defoliation treatments significantly decreased and the root weight were higher in partial 3 leaves or 4 leaves defoliation treatment but was not significantly different among treatments. Because T/R ratio decreased significantly as growth inhibition of above-ground part compared to underground part, it is considered easy to take rooting after plantlet plating. As the intensity of defoliation was strong, chlorophyll contents tended to decrease significantly. Reduction of the endogenous nitrogen by defoliation effectively led to promote floral differentiation at low temperature and short day condition. This promoted timing of budding and flowering and also induced uniform flowering after plantlet planting. Marketable fruit yield of 3 leaves defoliation treatment tended to be higher than the control.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.54-54
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• 2019

Apple (Malus domestica) is one of the most economically important fruits in Korea. But virus infection has decreased sustainable production of apple and caused the serious problems such as yield loss and poor fruit quality. Virus or viroid infection including Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV), Apple stem grooving virus (ASGV), Apple mosaic virus (ApMV) and Apple scar skin viroid (ASSVd) has been also reported in Korea. In many cases, apple is infected with virus and viroid with no specific symptoms, the damage caused by the virus are unaware significantly. In our research, we tried to eliminate viruses in the rootstock for the disease-free seedlings of the apple dwarfing rootstock M.9 and M.26. The method of virus elimination was meristem culture, heat($37^{\circ}C$, 6weeks) treatment and chemistry($Ribavirin^{(R)}$) treatment. The analytical methods commonly used for the detection of virus is Enzyme-linked Immuno-Sorbent Assay(ELlSA) and Reverse Transcription-polymerase Chain Reaction(RT-PCR). RT-PCR method was more 30% sensitive than ELISA method. Efficiency of method eliminate virus appeared meristem method > heat treatment > chemistry treatment. The higher acquisition rate of disease-free seedlings is 30~40% on meristem treatment. In meristem treatment, the apple dwarfing rootstock M.9 gained infection ratio of ACLSV, ASPV and ASGV were 45%, 60% and 50% respectively. In the apple dwarfing rootstock M.26, infection ratio of ACLSV, ASPV and ASGV were 40%, 55%, 55%, respectively. Based on our results, it was found that most effective method of disease-free seedlings apple dwarfing rootstocks was by meristem treatment than heat method and chemistry treatment.

• Journal of Bio-Environment Control
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• v.11 no.3
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• pp.127-132
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• 2002

Enhanced supply of $Ca^{2＋}$ as well as NO$_3$$^{[-10]}$ is known to restrict the uptake of the Na$^{＋}$ and Cl$^{[-10]}$ ion and ameliorate growth under saline conditions. This test was conducted to investigate the ameliorating effects of Ca(NO$_3$)$_2$ or CaCl$_2$ on the growth and yield of NaCl-stressed tomato plants grown in plastic pot filled with soil. All treatments except for the control were supplied with 80 mM NaCl fur two weeks after transporting. The saline solutions with nutrient were supplemented with either 0, 10 or 20 mM Ca(NO$_3$)$_2$ and either 0, 10 or 20 mM CaCl$_2$ during harvesting time from two weeks after transporting. Ca(NO$_3$)$_2$ or CaCl$_2$ application enhanced the growth such as plant height, fresh weight, dry weight, fruit number, and fruit weight, and yield of NaCl-stressed tomato, and also their effects increased greater as concentration of supplemented Ca(NO$_3$)$_2$ or CaCl$_2$increased. Yield increased in 20 mM Ca(NO$_3$)$_2$ compared with the others except fur the control. Photosynthetic rate in Ca treatments was lower than that of the control, but higher than that of NaCl treatment. Leaf chlorophyll content was higher in Ca treatments compared with the others, especially in younger leaf, while that was not affected by concentration of supplemented Ca. Ca(NO$_3$)$_2$ or CaCl$_2$ supply increased the $K^{＋}$ and $C^{2＋}$ concentration of tomato plants, whereas the Na$^{＋}$ transport to the leaves was inhibited. There was a strong increase in the $K^{＋}$/Na$^{＋}$ ratio in plants treated Ca(NO$_3$)$_2$, or CaCl$_2$. Cl$^{[-10]}$ content of plants was decreased by supplemental Ca(NO$_3$)$_2$ but Cl$^{[-10]}$ was increased in plants with CaCl$_2$compared with Ca(NO$_3$)$_2$. N concentration in plants of tomato increased with enhanced Ca(NO$_3$)$_2$ or CaCl$_2$supply, In conclusion, our study confirms the potential of Ca(NO$_3$)$_2$ or CaCl$_2$to alleviate NaCl-induced growth reductions in tomato.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.3
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• pp.135-152
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• 1975

The following informations are known from physical and chemical characteristics of orchard soils and nutritional diagnosis of orange leaves in Jeju. 1. Most orange orchards are located on terrace and cindercone thus soil moisture and microclimate of an orchard will greatly be affected by its topography. 2. Excessive well drainage, shallow soil depth, high content of gravels, low solid phase ratio and strong wind will give severe problem of soil moisture and wind errosion, thus the exte- nsion of soil depth is necessary for maintain nutrients, water and sufficient root volume. 3. Available soil water was significantly and positively correlated with organic matter content and clay content also contributes to available soil water. Vinyl mulching was greatly helpful for soil water conservation, wind errosion prevention, soil temperature increases during winter. 4. Abundant amphoteric amorphous allophane take a key role to fix phosphorus and also rations and thus it is the major factor to determine fertilizer efficiency. Lime and phosphorus must be applied in deeper soil layer. Release of filed phosphorus must be reevluated for availability. 5. Organic matter such as see weeds will greatly increase fertilizer efficiency and low fertilizer efficiency during spring may be related to available soil water. 6. Nitrogen was in superoptimum and Mg was enough but P and Ca were somewhat deficient according to leaf analysies while K was deficient according to fruit analysis. Phosphorus application increased sugar/acid ratio and potassium decreases rind percentage. 7. Manganese deficiency and toxicity appeared in a few places. Iron and boron were enough. Most places showed tendency of copper excess but some places showed copper deficiency. 8. Soiling after elimination of rock base, application of slow release fertilizer and abundant organic matter, vinyl mulching and drip irrigation will increase fertilizer efficiency greatly and fruit yield drastically.

• Korean Journal of Plant Resources
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• v.29 no.5
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• pp.598-603
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• 2016

The aim of this study was to elucidate the influence of vigor of a bearing shoot in ‘Bluecrop’ Highbush Blueberry (Vaccinium corymbosum L.) on growth characteristics of shoots and fruits. Bearing shoots were classified with BS (bearing shoot) and BMB (bearing mother branch). The vigor of bearing shoots were divided into four arbitrary categories; A was thin (< 6.0 ㎜) BMB and short (< 10 ㎝) BS, B was thin BMB and long (≥ 10 ㎝) BS, C was thick (≥ 6 ㎜) BMB and short BS and D was thick BMB and long BS. Shoots from D were longer (6.5 ㎝) and thicker (1.70 ㎜) than those from the others. Shoots of D had more leaves (5.8 ea) than those of the others. Leaf area of D was larger (13.5 ㎠) than those of the others. The first harvest of D was one week faster than the others. Ratio of big berry (>14 ㎜) from the long BSs was higher (B : 41.7, D : 46.8%) than that from the short BSs. Soluble solid content of small berrys did not show any different according to vigor of bearing shoots, but soluble solid content of big berrys of the long BSs was higher (B : 16.2, D : 15.6°Bx) than those of the short BSs. The thickness of BMB did not affect ratio of fruit size and soluble soild content. The long BSs would be proper than the short BSs for bearing bigger fruits.